A first known type of anastomosis foresees the use of suture thread for sewing and thus connecting the free ends of two blood or lymph vessels. Before proceeding with the suturing, it is obviously necessary to prepare the two blood vessels so that they present free ends, for example by cutting the vessels.
A second known type of anastomosis foresees that, to connect two blood or lymph vessels, they are evaginated by means of appropriate mechanical clamping devices and then joined by their inner walls. In this case too it is necessary to prepare the blood vessels so that their ends are free.
A third known type of anastomosis does not foresee direct contact between the two blood or lymph vessels to be joined, but uses prosthetic ducts, generally made from metal, to restore the continuity of the blood vessel or to create a diversion from one blood vessel to another.
The Applicant has found that the prior art devices for end-to-side anastomosis can be improved from various points of view.
Suture anastomosis, in fact, produces a more or less accentuated scar in the vessel in question, not perfectly restoring the original continuity of the vessel.
In addition, suturing involves the repeated perforation of the inner wall of the vessel, causing considerable trauma and hemorrhaging of the vessel. The hemorrhage caused by the suture is even more accentuated by the fact that the vessels to be anastomosed must necessarily be cut in order to have respective free ends.
Suturing also causes an at least partial slipping of the various layers that make up the anastomosed vessel. Blood vessels, like lymph vessels are in fact made up of several coaxial and overlapping layers of organic material.
Finally, precisely because of the essential difficulty of the suturing operation of two blood or lymph vessels, the suture anastomosis must be carried out by highly skilled surgeons.
Mechanical anastomosis by eversion, while being easier to perform than suture anastomosis, is also unable to restore the original continuity of the vessel.
Eversion of the vessel flaps can also cause the ends to break, particularly if the diameter of the vessels is greater than 3 mm or if they are affected by sclerosis.
Another complication, specific to blood vessels, is caused by the fact that the inside layers of the vessel ends, after being turned inside out and placed side by side, are no longer exposed to blood flow and therefore tend to atrophy and, in the most extreme cases, to become necrotic, causing pressure in the blood vessel which leads to narrowing.
Devices for end-to-side anastomosis which do not foresee direct contact between the two vessels being operated on present the drawback of involving direct contact between the metallic material of the prosthetic duct and the blood flow, which, as is known, can cause a risk of occlusion of the prosthetic duct by stenosis.
This drawback can be overcome by coating the metals used to manufacture the prosthesis with anti-stenosis substances which, however, do not always ensure against the subsequent formation of thrombi and the onset of acute thrombosis, exposing the patient to considerable risk.
In addition, apart from the known type of end-to-side anastomosis device used, an anastomosis operation always takes a considerable amount of time, exposing the patient to stress and other factors that can worsen his or her general physical condition.
Finally, in view of the highly invasive nature of known devices for end-to-side anastomosis, operations involving anastomosis are very often accompanied by abundant hemorrhage, sometimes requiring interruption of the circulation in the vessel being operated on.